-LRB- CNN -RRB- -- With President Barack Obama 's approval rating hovering in the low to mid-40s -- it was 45 % in CNN/ORC International 's recent poll -- Democrats in tough contests are largely keeping their distance from the president 's tarnished reputation .

And as Election Day has drawn closer , those differences have become more pronounced . Republican opponents are trying harder than ever to link their rivals to the president , forcing Democrats to visibly distinguish themselves from the White House .

Here are seven Democratic candidates who 've kept Obama on the sidelines :

1 . Alison Lundergan Grimes , Kentucky . As the Democrat challenging the Senate 's top Republican in a state that voted for Mitt Romney two years ago , Grimes has been perhaps the most high-profile candidate to keep her distance from Obama .

Most notably , she refuses to say whether she voted for the president , citing a matter of principle of privacy at the ballot box as her reason for not answering the question .

She 's been pressed about her support for the president because she 's made a blatant attempt to paint herself as the Democratic antithesis to the commander in chief .

`` I 'm not Barack Obama , '' she said in a campaign ad . `` I disagree with him on guns , coal and the EPA . ''

2 . Sen. Mark Begich , Alaska . Only 41 % of Alaska voters sided with Obama in 2012 , so Begich knows all too well that it 's not a smart strategy to be a champion for the president . In fact , he likes to think of himself more as a `` thorn . ''

`` I 'll be a thorn in his -LSB- posterior -RSB- , '' Begich told the Washington Post . `` There 's times when I 'm a total thorn , you know , and he does n't appreciate it . ''

Last week he admitted he voted for Obama but argued that his voting record was irrelevant because `` the president 's not relevant '' and will be `` gone in two years . ''

A limited role for Obama in his final campaign

And earlier this year he told CNN that he does n't need Obama to campaign for him in Alaska . `` I need him to change some of his policies . ''

Regardless of how big of a thorn he is , Begich has a tough hill to climb to win a second term .

He barely squeaked out a win in 2008 over then-longtime Sen. Ted Stevens , who at the time was buried in an ethics scandal . And a CNN/ORC poll from early October had Sullivan leading Begich , 50 % to 44 % .

3 . Sen. Mark Udall , Colorado . Udall was expected to have a smooth ride to re-election until Republican Rep. Cory Gardner entered the race in March .

Obama attended a Democratic fundraiser in Denver this summer , with half of the money raised going to Udall 's campaign .

But the senator was n't there .

His staff chalked up the absence to last-minute votes and legislative activity . The episode was foreshadowed somewhat when Udall refused to answer questions from CNN 's Dana Bash earlier this year over whether he 'd want to campaign with Obama .

In another example , Udall tried to take a stake out a firm line on airstrikes against ISIS , saying in September he wo n't give `` this president -- or any other president -- a blank check to begin another land war in Iraq . ''

4 . Sen. Kay Hagan , North Carolina . Hagan is running for a second term in a state that voted for Obama in 2008 but not in 2012 . As a result , she 's had to strike a balance between appealing to the pro-Obama factions in her state -- mostly concentrated in the college hubs and big cities -- and the more rural parts of North Carolina .

Senate math seems impossible to some Democrats

She exhibited this fine line in August , when she publicly criticized the president over the Veterans Affairs scandal in remarks released ahead of her speech at the American Legion . But when he showed up to also speak at the event , she warmly greeted him at the airport .

Last week she reluctantly admitted that the president has n't shown strong leadership . And when he visited North Carolina in January , she avoided him entirely .

5 . Sen. Mary Landrieu , Louisiana . Landrieu has tried to paint herself as someone willing to go toe-to-toe with the Obama administration , especially when it comes to energy policy .

She uses her position as chairman of the Senate Committee on Energy and Natural Resources as a major selling point in her campaign , and has sided with Republicans in pushing for the approval of the Keystone XL Pipeline .

In an ad , she 's seen saying `` the administration 's policies are simply wrong when it comes to oil and gas production in this nation . ''

Last year Landrieu declined to attend a visit by Obama to her state , though she still hitched a ride aboard Air Force One with the President on his way to Louisiana .

6 . Jeanne Shaheen , New Hampshire . Shaheen 's Republican challenger , Scott Brown , ca n't say one sentence without highlighting that Shaheen with Obama voted 99 % of the time .

Shaheen says she 's proud of her record , but she 's still not angling for a visit by the president . Asked whether she would want him to campaign for her , Shaheen said `` we have a lot going on . ''

`` I do n't think it makes sense for the president to come to New Hampshire , '' she continued , while answering the question at the CNN/NH1 debate last week . But she 's happily welcomed former President Bill Clinton , and Hillary Clinton is set to visit this weekend .

7 . Mark Pryor , Arkansas . Fighting to keep his seat against GOP challenger Rep. Tom Cotton , Pryor has also sought to strike a balance between the politics of his state and on the national level .

For example , he backs a minimum wage hike that 's on the ballot in Arkansas , but he opposes Obama 's proposal to raise the federal minimum wage to $ 10.10 .

Like other vulnerable Senate candidates -- such as Shaheen , Udall and Hagan -- Pryor has also called for travel restrictions to help prevent Ebola from spreading to the United States , a policy the Obama administration has not pushed .

Pryor made headlines earlier this month when he sounded unsure of how to answer a question about Obama 's handling of the Ebola situation .

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Democratic candidates in tough races are trying to keep President Obama at arm 's length

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Many of those candidates are fighting in largely red states

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Obama 's approval rating hovers in the mid to low 40s